Process for producting coal fillers

Abstract

A process for producing coal fillers, which comprises the steps of: (a) carbonization step, which comprises carbonizing crushed coal particles having a particle size of not more than 10 mm and an ash content of not more than 10% by weight by thermal decomposition at a temperature of 500° to 2,000° C.; and cooling the carbonized solids; (b) ultrafine pulverization step, which comprises preparing a slurry of the carbonized solids having a solids content of 10 to 50% by weight by adding a dispersion medium to the carbonized solids; and ultrafinely pulverizing the carbonized solids dispersed in the slurry to reduce the average particle size to not more than 5 μm; (c) agglomeration step, which comprises adjusting the solids content of the slurry to 1 to 20% by weight by further adding water to the slurry of the ultrafinely pulverized solids; adding an oil having a boiling point of not more than 150° C. to the resulting slurry in a ratio of 30 to 300 parts by weight of the oil per 100 parts by weight of dry solids; agitating the resulting mixture to agglomerate the carbonaceous matters with oil; and separating and recovering the agglomerates; and (d) drying step, which comprises drying the recovered agglomerates by heating them at 50° to 300° C. to evaporate the water and oil retained in the agglomerates; and cooling the dried agglomerates.

We claim: 
     
       1. A process for producing a coal filler, which comprises the steps of: (a) carbonization step, which comprises carbonizing crushed coal particles having a particle size of not more than 10 mm and an ash content of not more than 10% by weight by thermal decomposition at a temperature of 500° to 2,000° C.; and cooling the carbonized solids;   (b) ultrafine pulverization step, which comprises preparing a slurry of the carbonized solids having a solids content of 10 to 50% by weight by adding a dispersion medium to the carbonized solids; and ultrafinely pulverizing the carbonized solids dispersed in the slurry to reduce the average particle size to not more than 5 μm;   (c) agglomeration step, which comprises adjusting the solids content of the slurry to 1 to 20% by weight by further adding water to the slurry of the ultrafinely pulverized solids; adding an oil having a boiling point of not more than 150° C. to the resulting slurry in a ratio of 30 to 300 parts by weight of the oil per 100 parts by weight of dry solids; agitating the resulting mixture to agglomerate the carbonaceous matters with oil; and separating and recovering the agglomerates; and   (d) drying step, which comprises drying the recovered agglomerates by heating them at 50° to 300° C. to evaporate the water and oil retained in the agglomerates; and cooling the dried agglomerates.   
     
     
       2. The process as claimed in claim 1, wherein, in the step (b), the carbonized solids are pulverized to not more than 200 mesh previous to the preparation of the slurry. 
     
     
       3. The process as claimed in claim 1, wherein, in the step (b), the slurry is prepared by adding a dispersing agent, antifoaming agent or mixtures thereof together with water. 
     
     
       4. The process as claimed in claim 1, wherein, in the step (b), iron contents in the slurry are removed by the means of a magnet after the preparation of the slurry. 
     
     
       5. The process as claimed in claim 1, wherein, in the step (b), coarse particles are classified and removed by the use of a wet classifier after the adjustment of the solids content of the slurry. 
     
     
       6. The process as claimed in claim 1, 2, 3, 4, or 5, wherein the oil is a hydrocarbonaceous oil. 
     
     
       7. The process as claimed in claim 6, wherein the carbonaceous oil is toluene. 
     
     
       8. The process as claimed in claim 1, 2, 3, 4, or 5, wherein the oil is a freon. 
     
     
       9. The process as claimed in claim 8, wherein the freon is a trichlorotrifluoroethane. 
     
     
       10. The process as claimed in claim 1, 2, 3, 4, or 5, wherein, in the step (c), the oil is previously mixed with a compounding ingredient for rubber, a higher fatty acid of 12 to 24 carbon atoms or mixtures therefor. 
     
     
       11. The process as claimed in claim 1, 2, 3, 4, or 5, wherein the oil is previously mixed with a surface modifier for the ultrafinely pulverized particles. 
     
     
       12. The process as claimed in claim 11, wherein the surface modifier is a process oil for rubber, an activator, or a vulcanization accelerator. 
     
     
       13. The process as claimed in claim 1, 2, 3, 4, or 5, wherein, in the step (c), the oil recovered in the drying step (d) is used.